Abnormal processing of a recombinant feline leukemia virus envelope polyprotein and its interference with subgroup C...

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Feline leukemia virus (FeLV) is a retrovirus implicated in various feline cancers.
• The FeLV env gene encodes the surface glycoprotein (SU), crucial for viral entry and tropism.
• Recombinant FeLV constructs are used to study viral processing and function.

Purpose of the Study:

• To investigate the processing and cellular localization of a novel FeLV env recombinant protein (r6gp).
• To determine the functional consequences of r6gp expression on viral infection.
• To elucidate the molecular mechanisms underlying specific viral interference.

Main Methods:

• Generation of a recombinant FeLV provirus (r6gp) with a chimeric env gene.
• Expression and biochemical analysis of the r6gp env polyprotein in human-transfected cells.
• Immunofluorescence microscopy to assess protein localization.
• Infection assays using different FeLV subgroups (FeLV-B, FeLV-C) to evaluate interference.

Main Results:

• The r6gp env precursor was synthesized but not further processed or glycosylated, indicating retention in the endoplasmic reticulum (ER).
• ER retention of r6gp specifically interfered with FeLV subgroup C infection, but not FeLV subgroup B.
• Sequence analysis identified a specific region (region VI) in the chimeric env gene homologous to FeLV-C, suggesting its role in ER oligomerization and interference.

Conclusions:

• The study demonstrates a functional abnormality in a recombinant FeLV env gene, leading to ER trapping.
• Specific interference with FeLV-C infection is mediated by co-oligomerization of the trapped r6gp env protein with FeLV-C env proteins via region VI.
• These findings provide insights into FeLV env protein processing, tropism, and potential mechanisms in FeLV-induced lymphosarcomas.